docs: def timeout_at(clock, coro=None, *args):
      '''Execute the specified coroutine and return its result. However,
      issue a cancellation request to the calling task after seconds
      have elapsed.  When this happens, a TaskTimeout exception is
      raised.  If coro is None, the result of this function serves
      as an asynchronous context manager that applies a timeout to a
      block of statements.
  
      timeout_after() may be composed with other timeout_after()
      operations (i.e., nested timeouts).  If an outer timeout expires
      first, then TimeoutCancellationError is raised instead of
      TaskTimeout.  If an inner timeout expires and fails to properly
      TaskTimeout, a UncaughtTimeoutError is raised in the outer
      timeout.
  
      '''
      if coro:
          return _timeout_after_func(clock, True, coro, args)
  
      return TimeoutAfter(clock, absolute=True)